The present invention relates to a method of filtering a suspension to efficiently recover a liquid medium and obtain a condensed suspension.
Various filtration methods are used in filtering a suspension to recover a liquid medium. In the case of using of a filter material having a high density so as to carry out highly accurate filtration where a suspended substance is prevented from being leaked out to a filtrate, there will arise a problem that filtration efficiency is reduced in association with deposition of a cake on a filtration surface. To cope with this problem, there has been proposed a vibration filtration method for efficiently achieving concentration of the suspension and recovery of the filtrate, by preventing deposition of the cake on the filtration surface to thereby continuously conduct the filtration for a long period of time.
In such a conventional vibration filtration method as mentioned above, while a filtration operation is carried out by applying vibration to a filter equipment as a whole, deposition of the cake cannot be completely prevented, and furthermore, fastened portions of the filter equipment are loosened. Furthermore, there has been proposed an improved method of filtering a liquid by applying vibration to a filter material or its associated parts only, so as to prevent deposition of the cake on the filter material (Japanese Patent Publication No. 58-27972).
In the conventional filtration methods as mentioned above, while a rate of deposition of the cake onto the filter material may be reduced, it is necessary to reinforce the filter equipment or its associated parts to which vibration is applied, so as to endure the vibration. As a result, weight is increased to reduce energy efficiency, and the filter material is easily damaged by fatigue.